【作者】 周玲玲；

【导师】 孟亚利；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2010， 硕士

【摘要】 土壤盐渍化是限制农业生产发展的一个重要因素,合理利用及改善开发盐渍土地资源对农业发展具有重要意义。本研究采用盆栽方法,以耐盐品种中棉所44和盐敏感品种苏棉12号为材料,于2008-2009年在江苏南京(118°50’E,32002’N)南京农业大学牌楼试验站进行盐分水平(0%,非盐渍土壤；0.35%,轻盐渍土壤；0.60%,中盐渍土壤；0.85%,重盐渍土壤；1.00%,盐土)试验和水盐互作试验,研究目的是明确：(1)盐分胁迫对棉田土壤养分含量的影响；(2)盐分胁迫对棉田土壤微生物数量的影响；(3)盐分对棉田土壤酶活性的影响。主要结果如下：1.盐分胁迫对棉(Gossypium hirsutum L.)田土壤养分的影响土壤盐分胁迫显著降低了棉花生物量和籽棉产量,中棉所44受土壤盐分影响略小于苏棉12号。在棉花的整个生育期,土壤有机质、速效氮、速效钾、有效磷含量均随土壤盐分水平的提高呈逐渐下降趋势。相关性分析表明,土壤养分与棉花产量、棉株生物量呈显著或极显著正相关。说明盐分不利于土壤养分的分解转化与吸收,进一步抑制了棉花的生长及产量形成。同时,土壤干旱加重了盐害胁迫。2.盐分胁迫对棉(Gossypium hirsutum L.)田土壤微生物数量的影响从苗期到吐絮期,两个品种的根系活力、土壤细菌、真菌和放线菌数量均随土壤盐分的增加呈现逐渐下降的一致趋势,处理间差异均达显著水平。土壤水分亏缺加重盐胁迫影响,相同盐分水平下,正常灌水处理的土壤微生物数量显著高于相应干旱处理。耐盐性品种中棉所44各项测定指标的下降幅度均小于苏棉12号。相关性分析表明,各菌类数量与土壤有机质、速效氮、速效钾及有效磷含量之间均存在极显著的正相关关系,另外,各菌类数量之间、各养分含量之间的相关系数也达到极显著水平说明土壤微生物数量与土壤养分含量关系密切,是盐胁迫下棉花显著减产的一个重要原因,可作为土壤盐胁迫过程中的重要指标。3.盐分胁迫对棉(Gossypium hirsutum L.)田土壤酶活性的影响从苗期到吐絮期,两个品种的土壤脲酶、蔗糖酶、碱性磷酸酶、纤维素酶活性均随土壤盐分的增加呈现逐渐下降的一致趋势,处理间差异均达显著水平。土壤水分亏缺加重盐胁迫影响,相同盐分水平下,正常灌水处理的土壤酶活性显著高于相应干旱处理。耐盐性品种中棉所44各项测定指标的下降幅度均小于苏棉12号。相关性分析表明,土壤微生物数量、土壤酶活性与大多数土壤养分含量、棉花生物量、籽棉含量、根系活力和根冠比呈显著或极显著正相关关系。说明土壤微生物数量、土壤酶活性与土壤养分含量、棉花产量关系密切,是盐胁迫下棉花显著减产的一个重要原因,可作为土壤盐胁迫过程中的重要指标。更多还原

【Abstract】 Soil salinization is a key environmental stress factor that limits crop growth and population development, it is very important to exploit and utilize this soil. Two cotton cultivars with different salt-tolerance (CCRI-44, Sumian 12) were used, and five salinity rates (0%.0.35%.0.60%,0.80%,1.00%), standing for five levels respectively were applied. The study focused on:(1) Effects of salinity stress on cotton field soil nutrient content at different growth stages in cotton field; (2) Effects of salinity stress on cotton field soil microbe quantity at different growth stages in cotton field; (3) Effects of salinity stress on cotton field soil enzyme activity at different growth stages in cotton field. The main results were as follows:1. Effects of salinity stress on cotton (Gossypium hirsutum L.) field soil nutrient content at different growth stageUnder the same soil water treatment, with increasing of soil salinity, the content of soil organic matter, available nitrogen, available phosphorus and rapidly available potassium decreased. At the same time, the growth of cotton was inhabited by soil salinity stress. Root vigor, root dry weight, biomass, and seed cotton yield all declined with the increase of soil salinity. but R/S-ratio improved. Under the same soil salinity, the content of soil nutrient were much higher in well-watering treatment than in water stress treatment. Soil water stress aggravated the effects of soil salinity stress. Compared to Sumian 12, CCRI-44 was less affected by soil salinity at different growth stages of cotton. Correlation analysis showed that the seed cotton yield had a significant positive correlation with soil nutrient content, and the biomass was closely related with seed cotton yield. Soil microbe and soil enzyme, which are sensitive to soil salinity stress and closely related with cotton yield, are the important reasons of cotton yield decreasing and important indices to extent of soil salinity stress. These results reveal that soil salinity not only influences the soil nutrient the decomposition to transform and to absorb, but also directly affects the growth of cotton and the vield of cotton. 2. Effects of salinity stress on cotton (Gossypium hirsutum L.) field soil microbe quantity at different growth stageUnder the same soil water treatment, with increasing of soil salinity, the number of bacteria, fungi and actinomyces decreased. Under the same soil salinity, the number of soil microbe and activity of soil enzyme were much higher in well-watering treatment than in water stress treatment. Soil water stress aggravated the effects of soil salinity stress. Compared to Sumian 12, CCRI-44 was less affected by soil salinity at different growth stages of cotton. Correlation analysis showed that the seed cotton yield had a significant positive correlation with soil microbe and soil nutrient content, and the number of soil microbe was closely related with soil nutrient content, including the content of soil organic matter, available nitrogen, available phosphorus and rapidly available potassium. Soil microbe, which are sensitive to soil salinity stress and closely related with soil nutrient content, are the important reasons of cotton yield decreasing and important indices to extent of soil salinity stress.3. Effects of salinity stress on cotton (Gossypium hirsutum L.) field soil enzyme activity at different growth stageUnder the same soil water treatment, with increasing of soil salinity, the activity of urease, invertase, phosphatase, celluloytic enzyme decreased. At the same time, the growth of cotton was inhabited by soil salinity stress. Under the same soil salinity, the activity of soil enzyme were much higher in well-watering treatment than in water stress treatment. Soil water stress aggravated the effects of soil salinity stress. Compared to Sumian 12, CCRI-44 was less affected by soil salinity at different growth stages of cotton. Correlation analysis showed that the seed cotton yield, root vigor, root dry weight. R/S-ratio and biomass had a significant positive correlation with soil microbe and soil enzyme, and the number of soil microbe was closely related with activity of soil enzyme. Soil microbe and soil enzyme, which are sensitive to soil salinity stress and closely related with cotton yield, are the important reasons of cotton yield decreasing and important indices to extent of soil salinity stress.更多还原